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HP & 1/4 Estimate for my FC

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Old Oct 25, 2001 | 10:02 PM
  #1  
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HP & 1/4 Estimate for my FC

I fear the dyno! =)
I did a 4.4 0-60 on a gtech before it died (the gtech not the car).

My car has a lot of mods, most were all done at once when I got the car at 24k miles (2 years ago).

Street ported (tripoint)
3mm Apex seals
14lbs boost on stock turbos
Greddy 3" downpipe
3" high flow cat.
Greddy 3" cat back exhaust
Cold air box (tripoint)
K&N conical air filter
Greddy fuel computer
2 additional 550cc injectors
Greddy intercooler
98' spec intake pipe upgrade
aluminum flywheel
4.3 rearend*
17" Kenesis k5 wheels*

Full list of my mods:
http://www.hybit.com/~jriskin/rx7/car.html

* The 17" wheels and 4.3's cancel out the final drive ratio to very close to stock

Anyone want to take a stab at what I would be running 1/4 mile or how much RWHP I'm making?
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Old Oct 25, 2001 | 10:05 PM
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I would say high 12's or low 13's. Somewhere around 300 RWHP.
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Old Oct 25, 2001 | 11:06 PM
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Thats all? I was thinking more low 12's. But its hard to say. What would I need to do next to get a bit more performance? Its a street car so I can't go totally crazy here.

How much diff would lets say 16lbs lbs of boost make? I have the car set up with a 3 way switch hooked to the fuel computer that lets me pre-set 3 boost levels/fuel/timing maps.

I'm also running yokohama a022 tires which stick really well. The car hooks up nicely with 275's in the back.
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Old Oct 26, 2001 | 08:48 AM
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From what I can see, your weekest link is your stock turbo.
At 14 PSI you are maxing it out.
You could have more than 300 RWHP. Maybe 350?
That could put you in the low 12's with a good launch.
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Old Oct 26, 2001 | 01:58 PM
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yes, definetly consider running a t-04e with like 17 lbs of boost....then you'll tear people a new one!
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Old Oct 26, 2001 | 06:04 PM
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Yeah I've kept the twin setup for two reasons so far.

1. Reliability, I've had 3 rx-7's (one of each gen.) and over the years I've heard running more than about 14-15lbs of boost is just not advisable if you want your rotary to last any length of time.

2. Solo2, mid range power is still important, its hard enough keeping it under control with as much power as it already has!

But, if I thought the engine could take it, and I wasn't sacrificing too much low end grunt, then I might consider moving to a single turbo setup. Esp. considering how much less complicated the setup would be and I'm assuming it would be a bit lighter weight.
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Old Oct 26, 2001 | 06:31 PM
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FC?

Do you have an FC or FD?
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Old Oct 26, 2001 | 06:50 PM
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Hmm my last post didn't show up.

I'll summarize...

FD not FC!!! I've had all 3.

I spazzed when I posted the first time. Considering how much lighter the FD is it should make a big difference =)

SORRY for the confusion!
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Old Oct 26, 2001 | 09:50 PM
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It's not lighter. At least it's not lighter than my FC (2690 lbs.)
Anyway.... considering the improvements on the engine, I would say you should be well in to the 11's with a FD.
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Old Oct 29, 2001 | 06:31 PM
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Arrow

With sticky tires (ie drag radials/slicks) you could run low to high 11s. Most like put out mid 3xxRWHP range.

You say the your 17" rims cancel out your 4.33 gears. Why is that? Do you run a 50 series tire? I would have to look at the specs I have for the tires, but usually the 17s people put on are a lower series and come very close to the stock tire diameter. Either Tire Rack or Yokohoma will have this info on there site.
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Old Oct 29, 2001 | 07:07 PM
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Well the stock tire size is a 225 50 16".
I'm running a 275 40 17". My yokohama A032's have an overall outside diameter of 25.9" vs. 24.8" of the stock size. Thats roughly a 104.4% of the stock size.

So now take the stock 4.1 and divide by the 4.3 gears I have 95.3% lower ratio. Multiplied times the above number and you get 99.544% or .045% off.

So at 100mph i'm actually going 99.5mph.

Maybe I'm doing my math wrong somewhere but thats what I figured on my post.

Another odd point is that 1/2" tread by the time you wear all the way through it is roughly 2% off.
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